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Broken views and the 'jogged' dimension

Discussion in 'General Discussion' started by Paul W, Aug 8, 2018.

  1. Paul W

    Paul W Member

    I’m curious as to when the jog or ‘squiggle’ symbol became acceptable for dimensioning across a break.

    squiggle.jpg

    My old technical drawing textbook (pub.1986) showed no deviation from regular dimensioning for broken views. Alibre help calls this “Linear Foreshortened Dimensions”, and the jogged examples don’t really clarify things. I know that drafting standards change all the time, but is this a case of Solidworks does it so it must be right?

    The online help for Solidworks broken views states that “Dimensions that cross the break lines are broken automatically” and shows the 'squiggles' in the following image:

    SW break.jpg
     
  2. Lew_Merrick

    Lew_Merrick Alibre Super User

    It is really hard to make the case that "SolidWorks does it so it must be tight."
     
  3. Paul W

    Paul W Member

    Lew,

    The real question I am getting at is does this practice originate from the CAD industry? Unless you have seen a written standard mentioning it.
     
  4. Lew_Merrick

    Lew_Merrick Alibre Super User

    As somebody who learned how to dimension Broken Views in the days of ruling pens on linen, the "technique" dates (based on Drawings I have seen) at least to WWII (and I suspect much further back in time). My 2nd edition of French's Engineering Drawing lays out a number of "rules that should be followed."
     
  5. JST

    JST Alibre Super User

    The idea seems good, and may be old, I can check my copy of French, which I probably still have.

    I do NOT like how it is done above.

    In my view, the "squiggle" should be in line with the broken area of the view.

    Putting it in line with the break shows that the dimension is including the omitted length.

    Putting it elsewhere just adds complexity to the view, and does not make it clear why the "squiggle" is there at all.

    Perhaps a small point, but drafting is made up of a myriad of small points.
     
  6. HaroldL

    HaroldL Alibre Super User

    A quick check of ASME Y14.5M-2009 only mentions the "foreshortened" radius dimension and the linear dimension to indicate where the arc center is located. I suppose showing is break or foreshortening a linear dimension could be understood as preforming the same function.

    As I recall from my Technical College days when we drew a broken view on the drafting board we used a line under the dimension text to indicate that was a "not to scale" dimension when it crossed the break. Of course I was in the last class to use drafting boards and only used them for the 1st year, the 2nd year was all AutoCAD and Cadkey.
     
  7. Paul W

    Paul W Member

    Lew, JST,

    It would be interesting to see any old drawings using this method of dimensioning.
     
  8. Lew_Merrick

    Lew_Merrick Alibre Super User

    The only Drawings have using "foreshortened dimensioning" are either hand-drawn "J size" drawings (covered by NDA) or Generic CADD or General CADD drawings (also covered by NDA). Sorry.
     
  9. simonb65

    simonb65 Alibre Super User

    BS ISO 129-1; Technical Drawings. Indication of dimensions and tolerances - General Principals. states ...

    upload_2018-8-11_19-35-28.png

    But then again, it also quotes arc lengths, which is another current topic of debate on here ! ...

    upload_2018-8-11_19-37-53.png
    upload_2018-8-11_19-38-7.png
     
  10. Paul W

    Paul W Member

    So it’s probably a North American thing. Also my search led me to a S/W forum that says that the jogged dimension can only show up when they set things to "ANSI standard". Yet there seems to be no evidence of it in ASME standards (which took over from ANSI).
     
  11. Lew_Merrick

    Lew_Merrick Alibre Super User

    Paul -- Please remember that the American National Standards Institute was "decommissioned" in 2009. All "standards" for "Drawings" have been turned over to the American Society of Mechanical Engineers -- which means that nobody involved knows anything about Drafting (or Dimensionimg or Tolerancing -- far less conventional Drafting Practice!

    I was a member of ASME from 1975 through 1988. I quit because they ha no idea what the ",PE" at the end of my name meant. They only sent mail to me addressed to "Mr. Lew PE." Subscriptions to their "Research Jounals" had more than tripled while the "content" had been reduced to a bad joke.
     
  12. Paul W

    Paul W Member

    Alibre also sets defaults for the foreshortened dimensions depending on whether the drawing is on an ANSI or ISO sheet.

    Here is my test drawing set up on an ANSI B sheet with all the cases I could think of, including an arc (for radius) thrown in for good measure:

    (Note that I moved the default positions of the ‘squiggles’)

    ANSI test case.jpg
    I right-clicked the sheet name in the tree, selecting sheet properties, and picked ISO A3 as the template; then clicked “Update Existing Styles” (and Layers) for every drawing style conflict:

    now ISO test case.jpg

    The jogged dimensions were changed to double arrowheads but no symbol in the broken view.
     

    Attached Files:

  13. Lew_Merrick

    Lew_Merrick Alibre Super User

    To be clear there have been no ANSI Standards since 2009. Anybody saying otherwise is either ignorant or stupid (take your pick).
     
  14. Paul W

    Paul W Member

    On this topic, it's curious that Y14.5M-1994 was released as an 'ASME' standard, yet Alibre's Feature Control Frame shows 'ANSI Y14.5M-1994'.
     
  15. Lew_Merrick

    Lew_Merrick Alibre Super User

    Actually, the first release was as ANSI Y14.5-1967. The latest release is ASME Y14.100-2015.
     
  16. Paul W

    Paul W Member

    Harold,
    Do you recall what standard you might have been referencing in this older post:

    Thanks
     
  17. HaroldL

    HaroldL Alibre Super User

    Given how old that post is I honestly do not recall. From the thread it appears that v2012 was current and it was just before v2013 was released. I think the image may have been a screen shot from SolidWorks which did, at the time, apply a foreshortened dimension to broken views. AD 2013, from Max's post, was going to have broken views as an enhancement.

    In the current version of Alibre you have the option to toggle a foreshortened dimension in a broken view through the Change Dimension option of the menu that pops up when you click on a dimension.

    Y14.5 is still Y14.5, it only changed from ANSI to ASME. It is a required standard in ASME Y14.100 per 4.12.
     
  18. Paul W

    Paul W Member

    I would still like to know what standard this is from.
    _________________________________________________________________________________________________________

    Foreshortened Dimensions made it into the 2013 release; I guess Max listened to you Harold.;)
    foreshortened.JPG
    breaks.JPG
    The above is from the “Alibre Design 2013 – What’s New”. This was the big 2D drawing update. I have attached the PDF here as it is still mostly relevant and is a good reference for Alibre drawing features.
     

    Attached Files:

    NateLiqGrav likes this.
  19. NateLiqGrav

    NateLiqGrav Alibre Super User

    That was a very nice update!
    I hope drawing gets another comprehensive update.
     

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